1) Field of the Invention
The present invention relates to a technology for sending/receiving electronic mails.
2) Description of the Related Art
In recent years, electronic mail has widely been used in the world. The electronic mail can usually be sent with a desired attached file. Japanese Patent Application Laid-Open Publication No. 2003-134296 discloses a technique for sending electronic mails with files as attachments.
However, the electronic mails are intended to send and receive small-volume data such as text and not large-volume data such as image files or sound data. Simple Mail Transfer Protocol (SMTP) is used as a standard specification for electronic mail over the Internet. In SMTP, mail servers send and receive every piece of mail to and from each other. Therefore, if the volume of the attached file is large, large load is put on the electronic mail systems, and the electronic mail systems may crash or become slow. To avoid this, there is a tendency to impose limitations on the volume of an attachment. It that case, the sender is required to divide a large-volume data into two or more pieces and the receiver the required to combine the pieces.
On the other hand, File Transfer Protocol (FTP) is available for sending or receiving large-volume data. However, the FTP requires a special software called FTP software. The data is first uploaded into directory or so in the storage unit of the Internet server (FTP server). Since this requires beforehand preparation of disk space, creation of directories, the process is rather difficult, confusing, and complicated for a common man and also puts burden on the user.
Digital cameras, IC recorders etc. are becoming popular day by day. Therefore, means and method for easily transmitting large-volume data is being researched.